SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c44904ed64c06158b6a750b44e73e3a9d3d458e75ba6083f26052524cf075f9' 
  AND token = '+ZAWTNLv4vY+su+BV9DgSZG1AMHMMnrB2wJaMJLjl9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}